1. Field of the Invention
Embodiments of the invention relate to refrigeration devices, and in particular to user-control of refrigerator functions.
2. Related Technology
FIG. 1 shows a schematic diagram of a conventional refrigeration device. The device has an interior space 10 that is maintained at a desired temperature by a cooling system comprised of a compressor 12 and coils 14. The compressor 12 compresses a coolant gas into a liquid state. The liquid is then circulated to the coils 14, where it is allowed to expand to a gaseous state, thus removing heat from the coils and the surrounding atmosphere. A control system is used to control the operation of the compressor 12. The control system is comprised of a power controller 16 that controls the supply of power to the compressor 12 to turn the compressor 12 on or off. The power controller 16 may comprise a relay and associated circuitry. A temperature detector 18 such as a thermistor is located in the interior of the refrigeration device and provides a signal that is representative of the interior temperature to the power controller 16. A temperature selector 20 such as a variable resistor is also located in the interior of the refrigeration device and supplies a signal to the power controller. The temperature selector 20 is user operable and allows the user to specify a target temperature at which the interior is to be maintained. The power controller 16 switches the compressor between on and off states in response to the signals from the temperature detector 18 and the temperature selector 20. This method of operation is shown in FIG. 2 and is referred to herein as thermostat control. The control system is typically designed to provide a degree of hysteresis so that the cooling system is not constantly switched between on and off states in response to minor fluctuations around the target temperature. Some refrigerators further include an on/off switch that enables the user to shut off the compressor without the need to unplug the refrigerator from its power supply.